Build vs Buy Payment Infrastructure: Key Tradeoffs

Every engineering leader who has ever led a fintech startup eventually faces the same question: Do we build our own payment processing infrastructure, or do we buy it from an external provider?

This decision will shape the next several years of your business.

What Payment Processing Infrastructure Actually Involves

Payment processing infrastructure is more complex than most engineering teams anticipate. The technical scope goes well beyond the frontend checkout button.

It involves managing the card processing, acquiring or issuing banks, fraud detection and chargeback platforms, and regulatory compliance with the card schemes. For a full breakdown of how these pieces fit together, see payment infrastructure.

Most teams that start building assume the technical elements are manageable, then discover a domain with no shortcuts and no substitute for in-depth expertise.

Cost Comparison: Building Your Own Payment Processing Infrastructure

Building payment infrastructure in-house means taking on costs that extend well beyond the initial development phase, from upfront licensing to ongoing compliance and eventual re-architecture.

The Upfront Costs

Building your own payment processing infrastructure requires an immediate commitment to the card payment schemes, Visa and Mastercard, to begin processing transactions.

Furthermore, you'll have to secure a licence from the financial regulator and comply with PCI-DSS.

• EMI or PI licence: an electronic money institution or payment institution licence, depending on your country, is what legally permits you to hold and move customer funds, and it has to be granted before a scheme will certify you.
• PCI-DSS: the card industry's security standard for storing and transmitting cardholder data. Passing its Level 1 audit is a precondition for processing card transactions at volume, not a later clean-up task.

Moreover, engineers with acquiring and issuing experience are rare and expensive.

The Ongoing Costs

Beyond the immediate startup costs of building your own system, there are several other costs that will factor into the operational expenses of your business:

Regulatory compliance keeps changing, with AML, GDPR, PSD2, PSD3 and PSR all adding requirements over time; a vendor absorbs that learning curve, an in-house team does not.

Beyond regulation, a share of the roadmap goes to mandatory work that adds no customer-facing features but cannot be skipped:

• ISO 20022 migration
• Card scheme release cycles
• SCA changes
• Tokenisation upgrades

All of these land on the calendar whether or not the business asked for them.

Technology depreciation: a self-built stack needs partial rebuilding every few years, and this cost is rarely planned for.

Cost Comparison: Buying or Partnering with an External Vendor

Buying payment infrastructure from a third-party vendor brings a different cost structure: the per-transaction rate is typically higher, but many operational expenses shift off your balance sheet entirely.

However, the cost of fraud monitoring, chargeback management, certification with the payment schemes, and supporting new payment methods for customers are all costs that will fall on your shoulders if you go in-house.

At the volume of transactions that you will start with when you are in sub-scale, buying or partnering will ultimately cost less in the grand total than if you build your infrastructure in-house.

Speed to Market: In-House Build vs Vendor Timelines

Building your own payment processing infrastructure will take time to build, test, and gain certification from the card payment schemes.

Depending on how much experience your engineers have with acquiring and issuing banks, you might be looking at 12 to 24-plus months to get to market with your own solution.

By contrast, buying or partnering with an external vendor will drastically cut the time it takes for you to start receiving payments from your customers.

Most vendors selling white label payment gateway services can get you up and running in two to four months with PCI-DSS and GDPR compliance built into the go-live process.

Risk Comparison: What You Own vs What You Transfer

The choice between building and buying payment infrastructure redraws the lines of operational and regulatory responsibility.

Fraud and Operational Risk

When you go in-house to build your own system, you will have complete control over the backend fraud detection platforms.

The trade-off is that keeping those tools current against evolving fraud tactics is constant, ongoing work, not a one-time build.

Moreover, chargebacks will be your operational team's problem if you build.

On the buy side, a vendor typically provides the tools and handles the process, but the financial liability for a chargeback often still sits with the merchant, not the vendor.

You will also have to build a redundant system for your transactions to ensure that if one platform fails, the other can pick up the transactions where it leaves off.

A payment gateway outage stops revenue instantly, so the failover path is not optional infrastructure, and building it doubles part of the stack you have already paid to build once.

Compliance and Regulatory Risk

There is no such thing as a stationary regulatory regime in the payments industry. Every few years, there will be new regulations that come into play with AML, GDPR, PSD2, and the new PSD3 and PSR regulations.

Each one lands on a different part of the stack:

PSD3 and the accompanying Payment Services Regulation extend those obligations again, which means the compliance work is recurring engineering work, not a one-off project.

If you go in-house, you will have to be versed in all these regulations.

However, if you buy or partner with an external vendor, they will be responsible for ensuring that their systems are updated to comply with all regulatory requirements, which is their area of focus and expertise.

The Case for Building Payment Infrastructure In-House

At high transaction volumes, unit economics change in a meaningful way when a business owns the infrastructure behind its payments rather than renting it.

Factors like routing optimization, direct integration with the electronic payment schemes, and margin optimization via the elimination of intermediaries all contribute to an improved economic case for building out the infrastructure in question.

Analysis of the economics of gateways indicates that at transaction volumes of $100 million or more annually, a company can recoup the costs of building a custom gateway in the range of 18 to 24 months.

For companies whose payment offering is a key element of their product offering, building out the infrastructure that relates to payments can be a means of creating a defensible competitive position. A company that owns the technology that routes payments for its platform, or that builds out payout rules that are specific to its technology, can capture value from that ownership.

The Case for Buying Payment Infrastructure from a Provider

For most companies in growth stages, the engineering effort and compliance requirements for building the infrastructure required to accept payments from consumers will take engineering resources away from the development of the company's main product offering.

Furthermore, many of the leading vendors in the space for payment gateways already offer access to multi-scheme payment processing, alternate payment methods, and even emerging payment methods and technologies like account-to-account payments and stablecoins.

Account-to-account payments move money directly between bank accounts under open banking rules, bypassing the card networks and their interchange fees, and stablecoin settlement is starting to do something similar for cross-border flows.

Both are expensive to build alone and are typically included in a vendor's roadmap at no additional engineering cost to you.

When Fintech Startups Should Build vs Buy

Whether to build or buy payment processing depends on a specific set of conditions, not company size or ambition alone.

Build When These Conditions Are True

For a company to justify building out the infrastructure for its payments system, it must meet each of these conditions:

Buy When These Conditions Are True

A company should buy a payment gateway infrastructure vendor if it meets each of these conditions:

The Hybrid Path: Composable Infrastructure

Build vs buy is not a binary. A modular payment infrastructure approach lets you buy the commodity components from a vendor and build the differentiated ones in-house, mixing both paths instead of committing fully to one.

In practice, this means choosing a vendor whose setup lets you replace single parts with your own later, rather than one that locks you into its full stack. See how to avoid payment infrastructure lock-in for what to check before you sign.

If you do move from a bought setup to your own later, that move is a migration project in its own right. See payment infrastructure migration for how to plan it.